Well, I guess I will just have to decide betweena a packet station or an APRS station. I don't have the kind of money they want for those things. I have seen picture of bandpass/reject filters. They son't look that hard to make. Tunning them would be another, but I do have a spectrum analyzer. Plus they Look HUGE. about 10 inches by 20 inches. Oh well, guess I will just choose one. Thanks, Kevin Kc7hgn
--- In [email protected], Joe <k1ike_m...@...> wrote: > > My really rough guess is that you will need around 85dB of isolation > between the two stations. Using two antennas 25 feet apart is only > going to give you about 30dB of isolation. A bandpass filter at .64Mhz > off the center frequency will only give you around 10-20 dB more of > isolation. I think you will need either a bandpass/bandreject filter, > or possibly a notch filter on each station. > > My math is all best-guess, so please verify it before you go buying > equipment. I use a TX/RX Vari Notch 10" cavity for a similar > application, but they are expensive. I don't think you sare going to > find a cheap fix. > > Someone with more math skills can possibly verify my guess. > > 73, Joe, K1ike > > On 7/22/2010 7:10 AM, Kc7hgn wrote: > > I am not going to be able to stack the antennas. They Would be about 25-40 > > feet apart horizantal. I guess what I need is 2 bandpass filters. I think > > thats what I am looking for. Now the big question. Can I build them? And > > where would I find the information? If I can't build them, where would be > > an inexspensive place to buy them? I don't know of any Elmers in my area > > that know about bandpass filters, or one that would take the time to help. > > Thats why I am here. > > Thanks, Kevin > > Kc7hgn > > > > >
